The human apolipoprotein C-II gene was sequenced and found to contain four exons and three introns, with a major transcription initiation site located 26 base pairs downstream from a TATA sequence element. The third intron was found to be composed almost entirely of a novel 37-base pair minisatellite that is repeated six times. The minisatellite sequence was found to be present in approximately 60 different genomic locations. The minisatellite DNA sequence at three of these loci were compared and found to be highly conserved. In situ hybridization indicated that the minisatellite loci were clustered in the q13.3 band of chromosome 19. This is the first example of a chromosome- and band-specific repetitive element in the mammalian genome.